I. Field of the Invention
The present invention relates generally to audio speakers and, more particularly, to a speakerbar for use with a multichannel sound source.
II. Description of Related Art
The rapid emergence of shallow depth flat screen televisions has caused speaker manufacturers to rethink the ideal cosmetic shape of speakers to be used for home theater systems. Such home theater systems are intended to deliver three, five or even seven individual channels of sound with a like number of speakers per channel. Unfortunately, the use of separate speakers for each channel results not only in room clutter, but also difficulties in actually wiring the speakers to the multichannel sound source.
A new speaker design, however, has gained popularity recently, particularly when used with flat screen televisions. The industry term to describe these new speakers is “speakerbar”. Speakerbars typically include an elongated housing which fits below or above the television. Typically, the speakerbars have a width of two to four feet, are shallow in depth and short in height to both minimize visual intrusion and complement the flat screen television's shallow depth.
In order to accommodate the built-in internal or external multichannel sound source (receiver or amplifier), these previously known speakerbars have included at least one speaker for each channel of the multichannel sound source. Corresponding inputs on or in the speakerbar housing are provided to electrically connect the multichannel source to its associated speaker. Each individual speaker within or on the housing requires a minimum enclosure volume for a given bass extension. For example: to extend down to 100 Hz, the target high frequency cut-off for a subwoofer would require a housing three times as large as for three similar speakers compared to a housing for a single similar speaker.
The previously known speakerbars, however, suffer from several disadvantages: First, since the speakerbar itself is relatively small, only relatively small speakers may be used. Small speakers, especially those below 5¼″ diameter (or 4″×6″), have difficulty extending to 100 Hz (the maximum target crossover to a subwoofer), and reproducing a target of at least 100 decibels of output in the 100 Hz to 250 Hz (lower midrange) spectrum. Secondly, since each lower midrange speaker in the bar needs a minimum air volume to reach 100 Hz (or preferably even lower), there simply is not enough total air volume in the bar. To match properly with a subwoofer, each 5¼″ or 4×6″ speaker requires a minimum bar housing of approximately 18″. The result is that technology used in the previously known speakerbars causes them to fall short of the combination of low frequency response of at least 100 Hz and output of at least 100 decibels when more than two channels are included in the bar. A further disadvantage of the previously known speakerbars is a maximum limitation of five channels, probably due to limitations in the number of speakers which will fit in an acceptably sized enclosure. These five channels include the front left, front center and front right speakers, and left and right rear wall surround speakers. However, in today's technology, the number of sound channels has increased to seven channels by adding left and right side wall surround speakers. Furthermore, an attempt to accommodate seven channel sound by simply adding additional speakers to the speakerbar results in a further reduction of volume allowed for each speaker which further limits the bass response of the speakerbar. The only option with existing technology to reach down to 100 Hz and play at 100 decibels output is to increase cabinet size to unacceptable proportions for most of the population.
Conventionally, separate speakers for the left and right channel have a recommended separation of approximately two-thirds the seating distance from the television screen. If a listener sits the typical ten feet or greater distance from the screen, this would require that the left and right speakers be positioned seven or more feet apart from each other to create the proper soundstage. The previously known speakerbars, however, typically have a width of only two to four feet thus greatly diminishing the preferred width of the soundstage. Furthermore, the general consensus is that the speakerbar should not be wider that the television from an aesthetic standpoint.